package DataStructure.MapLearning.HashMapLearning.Demo01;

import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;

public class Demo {
    public static void main(String[] args) {
        HashMap<Integer, Integer> map = new HashMap<>();
        //System.out.println(map.put(1, 2));
        //System.out.println(map.put(1, 3));
        //System.out.println(map.remove(1));
        //Set<Map.Entry<Integer, Integer>> entries = map.entrySet();
        map.put(null, 2);
        map.put(1,null);
        map.put(null,null);
        map.remove(1);
        System.out.println(map);

        TreeMap<Integer, Integer> integerIntegerTreeMap = new TreeMap<>();


    }
}
